Previously Undiscovered Carbon Cycle in Polar Glaciers Could Become Significant Global Carbon Source

A new study by an international team of scientists from the U.S., Germany and Sweden revealed that a previously undiscovered source of carbon in the polar regions might greatly influence the current models of glacial contribution to the global carbon cycle.

The study, published in the journal Nature Geosciences, showed that microbes living in streams flowing over glacial surface can be a part of an undiscovered dynamic local carbon cycle that can become a significant source of carbon as the temperatures rise worldwide and microbial activity increases.

"It is believed that the impact of this material on downstream ecosystems will be amplified," said Christine Foreman, a researcher at Montana State University and an author on the paper, in a press release.

For the study, the researchers examined the ecosystem of a superglacial stream on the Cotton Glacier in Antarctica's McMurdo Dry Valleys. The dry valley represents roughly two percent of the surface area of Antarctica and is considered to be the largest ice-free region in the continent.

Superglacial streams are among the largest ecosystems on most of the world's glaciers. By studying the ecosystems in these streams, the researchers found that most of the carbon in them was produced by photosynthesizing bacteria.

Previously, scientists thought that the carbon being released into the streams came from ancient organic matter locked in the ice or from more modern sources, including dusts and soot blown in from fire or other sources around the world that deposited in the sea ice surface.

With their latest finding, the researchers noted that the sheer mass and surface area of glacial streams make it an important component of the global carbon cycle, despite harboring relatively small amounts of carbon.

As the global temperatures continue to rise, the polar region, which is very sensitive to high temperatures, the researchers believe that there would also be an increase in microbial activity. Due to this, they expect the release of more carbon from the microbial ecosystems of superglacial streams.